The results should allow assessment of the effects of metformin on insulin sensitivity and LH pulsatility (Day 1vs Days28-30) and on E2 and P suppresion of LH pulse frequency(Day 28 vs Day 35). The data will determine if GnRH pulse generator activity is altered by enhanced sensitivity to insulin and if E2 and P are now more effective in suppressing LH pulse frequency in PCOS. This should provide insight into the mechanisms of reduced GnRH pulse generator responses to E2 and P suppression in PCOS.